The field of the invention relates generally to warning devices used to alert motorists entering construction work zones prior to the motorists entering the portion of the roadway on which work is being conducted and devices to warn workers in work zones of encroaching traffic. There are extensive regulations and publications of various government entities describing, in great detail, methods and procedures for setting up safety devices to control traffic in roadway construction projects which are categorized as Traffic Control Zones. These Traffic Control Zones contain several discrete areas with different functions which include: 1) an advance warning area which puts motorists on notice as to what to expect ahead followed by a transition area in which the traffic flow is diverted from its normal path as the vehicles approach the actual work area, 2) a buffer area in which no work is performed and no vehicles or material are stored which provides two-dimensional buffering, that is distance in the direction of traffic flow from the end of the transition area to the beginning of the work area and a lateral buffering between the lane or lanes in which the traffic is flowing through the work area and the work area itself, 3) this is followed by the work area where the actual work takes place and equipment and material are stored and 4) the termination area in which the traffic is redirected into the normal traffic path along the roadway.
Roadway work areas are highly hazardous to both workers and motorists. Getting the attention of motorists as they approach the work zone as well as warning the workers of impending vehicle traffic are important steps in minimizing the risk of accidents and injuries arising from the unavoidable disruption of the traffic flow in work areas. In addition, varying approaches are necessary when taking into consideration the duration of the work to be performed on or adjacent to a roadway. The duration of work is typically characterized as follows: 1) long term stationary work which will require more than three days for the work, 2) intermediate term stationary work that requires more than one daylight period and up to three days to complete the work, or nighttime work lasting more than one hour, 3) short term stationary daytime work that occupies a location for one to twelve hours, 4) short duration work that occupies a location for up to one hour and 5) mobile work that moves intermittently or continuously along the roadway. It is important for a traffic safety device to be usable in as many of these types of work situations as possible.